There are diving mask assemblies known in the prior art which use lenses to aid viewing of watches, gauges and the like. One type of such a mask assembly is described in U.S. Pat. No. 3,787,113 and includes a mounting means for mounting a pair of corrective eyeglasses within the mask. The eyeglasses are removably and pivotally carried by the mounting means at the upper portion of the mask directly in the viewer's line of sight. Other types of underwater vision devices disclose corrective lenses supported by goggle-type support frames to be used primarily for recreational or competitive swimming and include lenses disposed directly in the viewer's line of sight, e.g., U.S. Pat. Nos. 4,373,788 and 3,944,345. There are add-on lenses as shown in U.S. Pat. No. 2,770,168, but distortion may occur when the wearer views objects laterally or downwardly removed from the normal line of sight. Lenses disclosed in the prior art do not compensate for this displaced line of sight.